This invention relates in general to connector devices and in particular to catamaran tiller-crossbar connectors.
Rudder manipulation of catamarans involves a linkage arrangement of a hiking stick connected to a crossbar and of the crossbar connected to tiller arms; there being one tiller arm-rudder assembly hinged to the transom of each hull portion. The tiller arm-rudder assembly is arranged for different planes of movement such that conventional steering of both rudders may be performed simultaneously by the crossbar while still enabling one rudder to "kick up" independently of the other when encountering an obstacle. Each end of the crossbar is fitted with a standard end cap and the adjacent end of the corresponding tiller arm is similarly provided with an identically styled end cap.
In order to permit the requisite variety and freedom of movement between crossbar and tiller arm, these adjacent end caps are held together by means of a connector. Since such connectors are subjected to a number of different force vectors of varying directions and magnitude during any sailing excursion of the catamaran, resistance to wear, durability, responsive control of the rudders and the ability to permit free movement of the crossbar and the tiller arm are important design factors of any suitable tiller-crossbar connector. Another factor to consider is that the standard end caps must be used, unchanged, in accordance with Hobie Class Association Racing Rules, in order for the catamaran to be of a "legal" design.
The following listed patents disclose construction concepts for sailboat steering systems which are representative of prior art attempts:
______________________________________ Patent No. Patentee Issue Date ______________________________________ 4,082,053 Woodward 4/04/78 4,027,614 Jones 6/07/77 3,388,611 Clary et al. 6/18/68 ______________________________________
Woodward discloses a catamaran with pivoting stern rudders which may be controlled by a crossbar connected to corresponding rudder tillers by means of inwardly offset pivots. While there is no specific reference to the design of the pivots, it is clear that standard end caps are not used and that the pivots are not arranged in any unique manner so as to accommodate the force vectors which act on the connector.
Jones discloses a sailboat construction which includes a retractable hydrofoil design. The crossbar connection to the rudders is by means of fixed tiller arms. Jones requires only a slight tilting of one rudder's pivot axis relative to the other to permit adjustment of position of the hydrofoils.
Clary et al. discloses a hinge connector for a control linkage which includes a plastic connector member having tubular end portions for receiving the free ends of a link and a lever having a reduced intermediate section forming a flexible hinge that permits relative pivotal movement between the lengths upon actuation of the linkage. The connector is a one-piece molded body of plastic or suitable elastic material and while the invention claims that the material used to be of suitable resilience and fatigue strength, the application is with a motor vehicle throttle control system and not with a catamaran. Consequently, the variety of force vectors associated with the motor vehicle are not as varied as with a catamaran and thus the hinge connector of this patent is of only limited relevancy.
Additionally, other currently used connectors are generally only one of two styles. The first style involves the use of a single synthetic disc placed between adjacent end cap surfaces and a straight bolt clamping the assembly together. Hemispherical members which conform to the interior recessed area contour of the end caps are used and a spring is disposed between a nut on the end of the bolt and one of the hemispherical members. The second style is virtually the same except that the single disc is replaced by two synthetic plate-like members which have abutting flat surfaces on one side and on the opposite sides, curved surfaces which fit the contour of the exterior surface of the end caps.
One disadvantage with these currently used styles is that with the spring tension set loose, the connectors have a double-jointed characteristic wherein the connector is allowed to pivot or swivel at both tiller and crossbar adjacent end caps. This double-jointed characteristic affects rudder-to-rudder alignment and when in steering a torque force vector is introduced into the crossbar by means of the hiking stick and there can be a feeling of backlash or lost motion in the steering system, whereas no-lash control is highly desirable. In the event the spring is tightened, such as to a fully compressed state, the backlash and double-jointedness can virtually be eliminated, but a disadvantage with this procedure is that the friction forces within the connector increase greatly and affect steering control when in light air and when the force required to steer is relatively low. In these conditions, a nearly frictionless feel is desirable. Another, and major, disadvantage of present connectors, exacerbated when tightened so that there is little or no spring play, is in the tendency to deform or fail both themselves and the end caps due in part to insufficient universal accommodation. Such universal accommodation is particularly needed when turning rudders to the maximum, resulting in an upturned tiller arm and its corresponding end cap becoming angularly disposed to the horizontal adjacent crossbar end cap, as single plane tiller arm and crossbar positioning is approached. Force from this extreme and insidious mechanical advantage elongates the end cap holes through which the bolt extends, and may even bend bolts or fracture end caps. It would be an improvement to such connector designs to structure connectors not susceptible to double-jointedness nor to the above prizing, and free of any feeling of backlash as well as providing a sensitive feel when in light air and when the force required to steer is relatively low. The design disclosed herein achieves these advantages as will be apparent from the description which follows.